Method for transferring heat between two process streams

Abstract

Shell and tube heat exchangers that include a baffle arrangement that improves the temperature profile and flow pattern throughout the exchanger and/or that are integral with a reaction vessel are disclosed. Methods for using the exchangers including methods that involve use of the exchanger and a reaction vessel to produce a reaction product gas containing trichlorosilane are also disclosed.

What is claimed is: 
     
         1 . A method for transferring heat between two process streams by use of a shell and tube heat exchanger, the shell and tube heat exchanger comprising a shell, a tube bundle within the shell with a chamber being formed between the tube bundle and the shell, the bundle comprising a plurality of central tubes and a plurality of peripheral tubes between the central tubes and the shell, an annular baffle having a outer edge, an inner edge and a plurality of peripheral openings formed within the outer edge and the inner edge, wherein the peripheral tubes pass through the peripheral openings; and a central baffle having a plurality of central openings and an outer edge and wherein the peripheral tubes pass between the outer edge of the central baffle and the shell and the central tubes pass through the central openings, the method comprising:
 introducing a first process gas into the chamber formed between the tube bundle and the shell, the first process gas passing through the central openings of the annular baffles and between the outer edge of the central baffles and the shell; and   introducing a second process gas into the peripheral tubes and the central tubes.   
     
     
         2 . The method as set forth in  claim 1  wherein the first process gas and the second process gas are in a countercurrent arrangement as they pass through the shell and tube heat exchanger. 
     
     
         3 . The method as set forth in  claim 1  wherein the shell and tube heat exchanger comprises at least about two annular baffles. 
     
     
         4 . The method as set forth in  claim 1  wherein the shell and tube heat exchanger comprises at least about two central baffles. 
     
     
         5 . The method as set forth in  claim 1  wherein the shell and tube heat exchanger comprises a second shell that is concentric to the first shell and has a radius greater than the radius of the first shell, the first shell and second shell forming an annular chamber between the first shell and second shell, the method comprising introducing a third fluid into the annular chamber. 
     
     
         6 . The method as set forth in  claim 1  wherein the ratio of the average axial distance between baffles D 1  and the diameter D 2  of the shell is from about 3:1 to about 1:3. 
     
     
         7 . The method as set forth in  claim 1  wherein the ratio of the cross-sectional area defined annular baffle to the cross-sectional area defined by the shell is at least about 1:10. 
     
     
         8 . The method as set forth in  claim 1  wherein the annular baffle has a central opening inward to the inner edge of the annular baffle and wherein the ratio of cross-sectional area of the central baffle to the cross-sectional area of the central opening of the annular is at least about 1:5.